Where does the coronavirus come from? After four weeks in Wuhan, China, experts fromWorld Health Organization (WHO) announced on February 9 that they had not yet been able to unravel the origins of the covid-19 pandemic. But several hypotheses emanate all the same from their observations carried out in the cradle of the epidemic.

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Two animals, but which ones?

Thus, according to these experts, the most probable hypothesis is that of a transmission of the virus from a first animal then a second, designated as “the intermediate host“, before contamination to humans. However, this track requires”more specific and targeted research“, according to Peter Ben Embarek, head of the WHO delegation to China.

In particular, it will be necessary to identify the two animal species involved in this chain of transmission. So far, the bat and the pangolin have already been singled out, but these assumptions must be verified.

The “exact role“of the Wuhan market in the spread of the virus remains”unknown“, concedes the WHO. This market, where live wild animals were sold, remains the first known focus of covid-19.

The frozen food trail

Another hypothesis was then raised: that of a transmission of the virus “through the frozen food trade“. For Peter Ben Embarek,”it would be interesting to examine if a frozen wild animal that has been infected could have been a potential vector“.

China has reported numerous samples in recent months “positive“to the coronavirus on food products imported from abroad. Contamination by the cold chain often mentioned by the country, because it tends to support the thesis of an importation of the virus.

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Leak from a laboratory?

On the other hand, the theory of a virus leak from a laboratory was judged “highly improbableThis thesis was notably defended by the administration of former US President Donald Trump. The latter had directly accused the Wuhan Institute of Virology, which conducts research on dangerous pathogens, of having let escape the coronavirus, whether on purpose or not.

No propagation before December 2019?

Last point : “there is not enough evidence […] to determine if Sars-Cov-2 spread to Wuhan before December 2019“Liang Wannian, head of the delegation of Chinese scientists, said at a press conference.

The central Chinese metropolis, at the epicenter of the outbreak in January 2020, was the place in the world where the first cases of covid-19 were reported. But several clues grouped together in particular in an American study evoked a possible circulation of the virus in Wuhan as of August 2019.

In France too, analyzes a posteriori chest scans or blood samples taken in hospitals have also reported the possible presence of the virus from December 2019 in Seine-Saint-Denis and from November 2019 in Alsace. So many presumptions that must be analyzed with precision in order to hope to trace a clear history of the epidemic.

“Need time and effort”

The WHO mission on the origins of transmission of the virus to humans must continue and the organization has already warned that it would be necessary to be patient before finding a possible answer. “We are in a process and we need time and effort to understand“what happened,” Dr Hung Nguyen-Viet, co-director of the human and animal health program at the International Livestock Research Institute in Nairobi, told AFP.

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But if the conclusions of the WHO are also eagerly awaited, it is because they should make it possible to better fight in the future against a next epidemic.